遍历Map的几种方式

#遍历Map的几种方式

方法一

for (String key : map.keySet()){
     System.out.println("key= "+ key + " and value= " + map.get(key));
}

方法二

Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
 while (it.hasNext()) {
     Map.Entry<String, String> entry = it.next();
    System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}

方法三 （推荐）

for (Map.Entry<String, String> entry : map.entrySet()) {
    System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
}

方法四

for (String v : map.values()) {
    System.out.println("value= " + v);
}

顺便把遍历proerties也说下，有点类似

初始化proerties

Properties prop = new Properties();
//TODO....

方法一：

Enumeration<String> eee = (Enumeration<String>) prop.propertyNames();
while (eee.hasMoreElements()) {
    String key = (String) eee.nextElement();
    String value = prop.getProperty(key);
    System.out.println("key= "+ key + " and value= " +value);
}

方法二：

Enumeration<Object> enu = prop.elements();  
while (enu.hasMoreElements()) {  
    Object value = enu.nextElement();  
    System.out.println(value);  
}
`

方法三：

Iterator<Entry<Object, Object>> it = prop.entrySet().iterator();  
while (it.hasNext()) {  
    Entry<Object, Object> entry = it.next();  
    Object key = entry.getKey();  
    Object value = entry.getValue();  
    System.out.println("key   :" + key+",value:"+value);  
}